How Frequently Do the Results from Completed US Clinical Trials Enter the Public Domain? – A Statistical Analysis of the ClinicalTrials.gov Database

POLS: July 15, 2014

Background

Achieving transparency in clinical trials, through either publishing results in a journal or posting results to the ClinicalTrials.gov (CTG) web site, is an essential public health good. However, it remains unknown what proportion of completed studies achieve public disclosure of results (PDOR), or what factors explain these differences.

Methods

We analyzed data from 400 randomly selected studies within the CTG database that had been listed as ‘completed’ and had at least four years in which to disclose results. Using Kaplan-Meier curves, we calculated times from completion to PDOR (defined as publishing the primary outcomes in a journal and/or posting results to CTG), and identified explanatory variables predicting these outcomes using Cox proportional hazards models. Read More